Administrator op



(No Model.)

. L. L. SMITH, Decd.

E. L. SMITH, Administrator. ELECTRIC DEPOSITING GELL.

No. 898,526. Patented Nov. 2'7, 1888.

WlZnssses: Invenlor:

Wgww? UNITED STATES PATENT QFFIQEO EDVVARI) L. SMITH, OF ANSONIA, CONNECTICUT, ADMINISTRATOR OF I LUTHER L. SMITH, DECEASED.

ELECTRIC DEPOSlTlNG-CELL.

:riL-ECIFICATION forming part of Letters Patent No. 393.526, dated November 27, 1888.

(No model.)

To all whom, it may concern.-

Be it known that LUTHER L. SMITH, late of Ansonia,in the State of Connecticut, deceased, invented a new and useful Improvement in Electric DepositingCclls, of which the follow ing is a specification.

The said invention relates to an improvement in the method of depositing copper for the purpose of refining it, separating and saving the precious metals that it contains. The depositing vat or cell is made of wood, and may be of any convenient size and shape to meet the requirements of the case. It must be lined with some insulating material, and not with metal. An article sold as roofing-cement, made from CORII'ULIQIS suitable for the purpose. Other materials may be used. Such a vat is represented in Figure] of the drawings, hereto annexed. The solution used is the ordinary acid solution of sulphate of copper used in ordinary electrotyping operations. The copper to be deposited is first east in plates of the proper size and form. The plates so cast are not suspended vertically in the solution, as is usually done, but are placed horizontally. As it would not be practicable in many cases to cast the plateslarge enough to give a snflicient amount of surface, several plates are laid side by side, so as to form one large plate. The layers are placed one above the other at a suitable distance apart. In the vats in actual use this space between the layers is one and a half inch. The first or bottom layer rests on two strips of wood running lengthwise of the vat. The plates are made of a length a little less than the width of the vat. -After the plates are placed in position on the strips, other strips are placed on the ends of these plates, and these strips support another layer of plates. In order to separate and save the insoluble foreign substances, including silver or gold, from the copper, cotton cloth is stretched from one strip to the other between the layers of copper.

Fig. 2 represents, removed from the vat, a section of a series of layers of copper plates extending across the vat. a a represent two plates of the top layer. Thelower layers are represented by the dark lines below. b b represent the strips of wood which separate and support the plates. lines below the dark lines represent the cloth screens between the layers of copper. A sec tion of one of these screens with the supporting-strips is represented by Fig. 4..

Fig. 3 represents the layers of three vats and the manner of connecting them to form a con nected series of cells.

A vertical space, 0, at the left of each series of layers represents a narrow chamber formed by a partition across the end of each vat. Aftor the copper plates have been placed in position the vat is filled, through the chamber, with the solution of sulphate of copper, an opening through the bottom of the partition allowing the solution to enter the vat at the bottom and rise through the plates until the top one is covered. Now taking the top plate as an anode, a conductor is brought from a dynamo machine or battery and connected with this plate. The other pole of the dynamo is connected with the bottom plate. The spaces between the plates containing solution form separate cells in series, the plates forming condoctors to connect the cells. The copper is taken from the under surface of the top layer of the plates and deposited on the upper suraee of the next layer below, and so on through the whole series, the under surfaceofthe plates being anodes and the upper ones cathodes. Theinsoluble foreign matters in the copper, including gold or silver, are liberated as the copper is dissolved and fall upon the filters or screens, thus allowing pure copper only to be deposited on the upper surfaces of the plates. Then the original copper of each plate has been transferred to the plate below, or when the accumulation of foreign matters upon the filters is sufficient to interfere with the progross of the depositing, the solution is to be drawn off either through the chamber 0 by a pump or siphon, or through a cock at the bottom of the vat. The plates and the filters with their contents can then be removed. If the copper has not been wholly deposited, the deposited copper can be separated from the undepositcd copper, and the latter be again placed in the vat, to beagain acted upon.

Fig. 3 shows the manner in which the plates in several vats are connected into a series of The horizontal broken cells, the lower plate of one vat being connected with the upper plate of another vat.

The number of cells in a circuit will be determined by the electromotive force of the current and the resistance of the circuit.

The method above described for arranging depositing-cells horizontally has several important advantages over the common vertical arrangement. The silver or other foreign insoluble matter is easily'collected and removed. The space required for a given amount of de positing is relatively small. So, also, is the amount of solution required. The connection between the cells in one tank is made by the copper plates themselves. The copper is easily handled and prepared for the vats.

It is well known that it is important that the density of the solution between two plates, which form an anode and opposite cathode, should be the same between all parts of the plates, in order to insure upon the whole surface of the cathode a uniform deposit of copper in thickness and quality, andin order, also, to insure a uniform consumption of copper from the whole surface of the anode. It is important, also, in order to insure a uniform specific resistance in the solution between all parts of the plates; but inasmuch as a solution of sulphate of copper is of greater specific gravity than the free acid,which is liberated by the deposition of the copper upon the surface of the cathode, such acid rises to the surried on for a short time only, this is not a se-' rious matter; but when the plates are large, and thick deposits requiring several days are to be formed, these non-uniform conditions become very important. The free acid attacks the upper portion of the plates more rapidly than the lower portion, and the deposition goes on most rapidly on the lower portion of the cathode. To obviate these difficulties, it is usual to provide some means to keep the solution in motion, applied sometimes to each cell and sometimes to the whole series of cells, the liquid being made to flow continuously through the whole series of cells. The former mode is objectionable, because it requires a complicated apparatus to act separately on each cell of a series, perhaps of several hundred. The latter mode is objectionable, because it requires a free-liquid connection between the series of cells.

In the arrangement herein described it is unnecessary to provide any means to keep up a circulation of the liquid, for the free acid liberated over the whole horizontal surface of the cathode in each cell rises directly through the solution and the screen to the surface of the anode above and acts uniformly over its whole surface. The deposition also takes place uniformly over the whole surface of the cathode, and thus uniform chemical and electrical conditions are secured over the whole surface of each plate and uniform liquid resistance between all parts of the plates, and the action of the cells is entirely automatic. There is another result of considerable importance due to the fact that a considerable number of cells are placed in a vertical series. It is well k nown that electrode deposition proceeds more rapidly at a moderately-high temperature than at a low temperature, and means are some times adopted to apply extraneous heat; but in the arrangement herein described the heat generated by the current maintains the temperature sufficiently high to insure rapid deposition, the loss of heat through the walls of the tank and at the upper surface being very small and much less than where an artificial circulation of the liquid is maintained. A single horizontal cell would present conditions most liable to the loss of heat, and any mechanical arrangement for maintaining a circulation of the liquid would also entail a loss of considerable importance.

Another advantage of the described arrangement is that no change in the condition of the solution from evaporation takes place in the cells, the evaporation of the liquid above the top plate not affecting the liquid in the cells themselves. As the process of deposition goes on interruptedly for many days, the loss by evaporation must be considerable and must constantly change the density of the solution where the cells are vertical. In the arrangement herein described no change occurs in the cells from evaporation of the solution.

What is claimed as the invention of the said Luther L. Smith is A vertical'series of horizontal electro-depositing cells formed by horizontal plates of the metal to be deposited, separated and supported by insulating-supports, and immersed in an electrolytic solution, with screens interposed between the successive plates, substantially as described, whereby insoluble matters are arrested as they are liberated from the lower surface of the upper plate in each cell by the combined action of the said solution and the electric current.

Witnesses:

H. A. \VILLARD, W. A. FELLOWS.

IIO 

